中文摘要：

为研究生物柴油对柴油机排放颗粒氧化特性的影响,利用MOUDI采样器采集不同燃料的排气颗粒物,分别借助透射电镜（TEM）、热重分析仪（TGA）研究颗粒物微观形貌及氧化特性,再利用高倍透射电镜（HRTEM）分析氧化过程中颗粒物微观结构的变化。结果表明：相比于纯柴油,燃用B20燃料（0#柴油掺混20%生物柴油）后,排气颗粒整体尺寸减小且局部重叠和堆积效应减弱,初始粒子粒径增加,全负荷工况下,B0、B20的初始粒子平均粒径分别为32.08 nm、43.42 nm;随着生物柴油掺混比增加,颗粒物起燃温度及最大氧化速率温度依次降低,B0、B5、B10、B20对应的最大氧化速率温度分别为605℃、572℃、524℃、507℃,但B20颗粒物氧化速率峰值较B0增加了约35%,表明B20颗粒物氧化速度加快;颗粒物氧化后的微观结构变化表明,掺烧生物柴油,颗粒物多核结构增多,内核尺寸约为5 nm,多核颗粒内核的氧化活性高于外壳且氧化过程中出现中空胶囊状结构,掺烧生物柴油使颗粒物氧化活性增加。

英文摘要：

In order to explore the impact of biodiesel on the oxidative characteristics of particulate matter emmited from diesel engine,MOUDI impactor was used to collect the particulate matter emitted from engine fueled with diesel-biodiesel blends. Then transmission electron microscope（ TEM）and thermogravimetric analyzer（ TGA） were used to analysis the nano-morphology and oxidative activity of diesel-biodiesel blends particulate matter. Also,the impacts of biodiesel on nano-structure and its changes in the oxidation progress of particles were explored by using high resolution transmis-sion electron microscope（ HRTEM）. Results showed that the particle size of B20（ 0# diesel blend with 20 percentage biodiesel） decreased compared with pure diesel particles and the overlapping phenomenon of particles was weaken. However,the initial particle size increased and the mean size of initial particle of B0 and B20 were 32.08 nm and 43.42 nm respectively. The TGA curves showed that with the increase of biodiesel percentage,the light-off temperature of particle decreased and the weight loss peak temperature decreased. The corresponding temperature of weight loss peak of B0、B5、B10、B20 were 605 ℃,572 ℃,524 ℃,507 ℃,respectively,and the weight loss rate peak of B20 increased about 35% compared with B0,which indicated that the particles of B20 was oxidized faster. Finally,biodiesel tends to produce more multiple cores structure and its size is about 5 nm.Also,its oxidation activity is higher than the outer shell and the hollow capsule structure will appear in the oxidation process. The oxidation activity of biodiesel particles is higher than diesel particles.